unless i'm mistaken, you can't really snap polygons to a nurbs curve... all curves in maya are nurbs based, and aren't really compatible with polygons because they're two separate entities. instead of creating polygons you might want to look at creating a loft (select the the first curve you want, then add the second curve you want to loft along to your selection, then go surfaces--> loft). from there you can convert that geometry to polygons and it should keep relatively the same shape.